[R] Newbie to R: would like to solve a problem

[tom wright]

I often use R to create graphs for my web applications which are
normally developed in PHP. I use the PHP command "exec" to shell out to
the R script, passing any parameters on the command line. The params are
then available in R using the commandArgs function.
How to get the data back is another problem, when creating graphs its no
biggy, I just create the graph as a file (using bitmap(type='png254') as
the output device since png() wont function without an X environment).
For simpler numeric data I guess at the worst you could write that to a
text file then parse that but there may be better ways.

On Fri, 2006-12-05 at 12:39 -0700, Shawn Mikula wrote:
> Using R for this would be a bit bone-headed since it is not ideally suited
> for web apps.  Look at an active scripting language like PHP.  I'm not sure
> if Geocities provides for server-side active scripting languages, in which
> case you will have to host your site elsewhere.
> 
> 
> 
> ----- Original Message -----
> From: "percy tiglao" <prtiglao at gmail.com>
> To: <r-help at stat.math.ethz.ch>
> Sent: Friday, May 12, 2006 11:07 AM
> Subject: [R] Newbie to R: would like to solve a problem
> 
> 
> > Hello, I am very new to R (read the introduction a few hours ago), but
> > experianced in several other languages (including Scheme, C, ObjC and
> > C++, Java and Javascript) and I was wondering how to approach this
> > problem:
> >
> > I am making a training calculator for a Video Game I play. Basically,
> > I want to calculate the probability of killing an enemy within x hits,
> > to help determine which is the best monster to train on in this game.
> >
> > The current implementation
> > (http://geocities.com/dragontamer5788/maple2.html) uses the normal
> > curve to estimate just about everything. Not necessarily a bad idea
> > for when it takes 10 or 15 hits to destroy a single enemy, Central
> > Limit Theorm kicks in and normal curve is probably a good idea, but my
> > gut feeling is that it is not accurate for estimating kills in 1 or 2
> > shots (which happens in the majority of "training" monsters), or the
> > probability of Knockback (which is always determined by a single
> > shot).
> >
> > The (simplified) function to represent the damage would be:
> >
> > sdmg <- function(min, max, skill){
> >  if(runif(1) > .4) (runif(1) * (max-min) + min) * skill
> >  else (runif(1) * (max-min) +  min) * (skill+1)
> > }
> >
> > total_damage <- function(min, max, skill, num_attacks){
> >  total <- 0
> >  for(i in 1:num_attacks){
> >    total <- total + sdmg(min, max, skill)
> >  }
> >  total
> > }
> >
> > --------------------
> >
> > The above is how damage is calculated. So the probability distribution
> > looks like 2 rectangles next to each other, one with height .6 and the
> > other with height .4. Sdmg is a helper function, because some attacks
> > attack 2 or 4 times in a single turn.
> >
> > Though, I dont want the simulation (what I'm doing with the runif
> > here). I'd like to calculate the probability distribution of
> > total_damage, total_damage + total damage (the convolution,
> > representing 2 hits), and so on till about 5-8 hits (then I can just
> > use normal curve in the web-calculator I'm making), then have a
> > polynomial function estimate the probability distributions based on
> > min, max, and skill. (So I can make my online calculator estimate the
> > probability of killing enemies)
> >
> > Erm, I know it is a lot to ask for, but how would I go about making
> > this in R? And if R isn't the right tool for this, is there any other
> > tool you'd reccomend? Cause doing convolutions by hand sucks.
> >
> > Thanks a lot for reading this long message :) And thanks in advance
> > for your help.
> >
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